I posted about getting a new used 747, I could never get my 747 to get the milage my 288 does. I have been playing today and on a level straight hyway 70mph 747 map 70.6 288 62.4 map kpa both are fairly good tuned chips same driving condition wind and all tempetures . if this interests you and you have a 288 it my do better in a v8 I have a v6. burn you a been and see if the 288 runs at a lower map than the 747, there is something different in the two ecms that make the 288 run at a lower map what I don't know 2 mpg differents at nothing to laugh at.